Furnace



R. L. BEERS Aug. 13, 1940.

FURNACE 2 Sheets-Sheet 1 Filed Jan. .17, 1938 m m w S R E E B L F- c Y O R Patented Aug. 13, 1940 FURNACE Royce L. Beers,.Birmin'gham, Mich, assignor .tc

Detroit Stoker poration of Michigan Company, Mcnroe, Mich, a cor- Application January 17, 1938, Serial No; 185A6l 3 Claims.

The invention relates to that type of industrial furnaces in which air for supporting combustion is supplied at more than atmospheric pressure. More particularly, the invention re 5 lates to furnaces which are provided with the sprinkler type of fuel feed and in which the fuel bed supported on the grate offers less resistance to the passage of air therethrough than with many other types of feeders.

It is well understood in the art that to secure the greatest efficiency, it is desirable to limit the quantity of air passing through the furnace as nearly as practical to that required for fully supporting combustion. However, if the air is not intimately commingled with the fuel gases, a greater quantity will be required to avoid imperfect combustion and the generation of smoke. It is also necessary to properly proportion the quantity of air passing upward through the fuel feed and that which is supplied above the fire. Where the air is supplied at more than atmospheric pressure as by means of a fan, a portion of the supply is admitted to a normally closed chamber beneath the grate and another portion above the fire.

It is the object prove the efiiciency of the furnace by more accurately controlling the relative quantities ofair which are admitted respectively beneath and above the grates. It is a further object to render the combustion of fuel gases more complete by creating a high degree of turbulence in the combustion chamber. While my improvements may be applied generally to any type of furnace, they are particularly advantageous with furnaces having the sprinkler type of fuel supply and where, as above stated, the fuel bed on the grates is less resistant to the passage of air therethrough than with other types. The invention, therefore, consists in the construction through which such objects are attained, as hereinafter set forth.

In the drawings:

Figure 1 is a diagrammatic perspective view illustrating a furnace to which my improvements are applied;

Figure 2 is a vertical longitudinal section through a portion of the furnace;

Figure 3 is a horizontal section substantially on line 3-3 of Figure 2;

Figure 4 is a vertical cross section on line 4-4 ofFigure 2.

As illustrated, A is the furnace provided with horizontal grates B with an ash and air chamber C therebeneath normally closed by a tight fitting door or doors D. The fuel is fed from a hopper of the present invention to im- (Ci. Mil- E to a rotary impeller F by which it is thrown into the furnace chamber and distributed over the grates B. As the detailed construction of this sprinkler feed forms nopart of the present invention, it is only illustrated diagrammatically.

The air for supporting combustion is supplied by a fan G capable of delivering air at a predetermined pressure above atmosphere, and as illustrated is located in rear of the furnace chamber. A conduit H extends from the fan to the chamber C and branch conduits I lead to the combustion chamber above the grates. In the diagrammatic illustration the conduit I extends to the front of the furnace where it is connected to a transversely extending conduit J having upward extensions K and K on opposite sides of the fuel feed. Nozzles L and L connected to the extensions K and K are directed into the combustion chamber and preferably diagonally across the same from the front corners to the opposite rear corners. Thus, the currents of air crossing in the central portion of the combustion chamber will create a high degree of turbulence which will thoroughly commingle the gaseous fuel with the air for supporting combustion. If, however, the air delivered through the conduit H to the chamber C should attain full pressure in the latter, this would cause too rapid passage through the fuel bed with a corresponding increase in rate of solid fuel consumption and with insufficient supply of air above the fire to consume all of the combustible gases. Such result is prevented by restricting the passage from the conduit H to the chamber C, preferably by a damper M. This may be so adjusted as to obtain just the desired pressure in the chamber C, while the air discharged through the nozzles L and L will be at high pressure, correspondingly increasing the velocity of the jets and the turbulence caused thereby.

As shown in Figures 2, 3 and l, the air from the fan enters a conduit H which expands in width to deliver porticns into the chambers C and C upon opposite sides of a central wall C At the top of this wall and just beneath the grate is a conduit 1 which extends to the front and there is connected to a cross conduit J having risers K connected with the nozzles L There are also upwardly extending passages N in the rear wall of the furnace connecting with cross passages N and passages N extending longitudinally in the side walls toward the front. A series of discharge ports N lead from the passages N'and'N into the furnace chamber and furnish additional air for supporting combushaving a tion above the fuel bed. Proper proportioning of the air through these various passages is accomplished by the dampers M controlling the air entering the chambers C and C and dampers O in the passages N. The operation of this construction is similar to that above described in connection with the diagrammatic representation, but has the additional advantage that air for supporting combustion is introduced along all sides of the furnace chamber above the fuel bed, while the cross jets produce the desired turbulence. It is also customary with the rotary impeller sprinkler type of fuel feed to pass air with the fuel into the front of the furnace chamber, thereby effecting still further distribution into the combustion gases.

With the construction as described, the total quantity of air introduced into the furnace may be limited to that which is necessary for properly supporting combustion, while the relative amounts entering the combustion chamber through the fuel bed and through the ports above the fire can be accurately proportioned. This, together with the high degree of turbulence caused by the crossing relatively high pressure air jets, will insure fairly complete combustion of the fuel.

What I claim as my invention is:

1. In a furnace, the combination with a front central opening through which fuel is fed and a grate for supporting the fuel bed, of a conduit extending transversely across said front adjacent thereto on the inner side thereof and below the top of said grate forming a hearth plate, means for supplying to said conduit cool air at a predetermined pressure above atmosphere, means for supplying air at lower pressure to the chamber below said grate, vertical conduits rising from said transverse conduit on opposite sides of the fuel opening, and nozzles at the upper ends of said vertical conduits for discharging the higher pressure air rearwardly over said grate the air thus discharged having previously cooled said hearth plate.

2. In a furnace, the combination with a front having a central opening through which fuel is fed, a grate for supporting the fuel bed, and a normally closed chamber beneath said grate, of a conduit extending across said front adjacent thereto on the inner side thereof and below the top of said grate forming a hearth plate and a reenforcement for said front, means for supplying to said conduit cool air at a predetermined pressure above atmosphere, vertical conduits rising from said transverse conduit on opposite sides of the fuel feed opening, nozzles at the upper ends of said vertical conduits for discharging high pressure air and directing the same diagonally across the combustion chamber, a connection between said air supply means and the chamber beneath said grate, and means for restricting said connection to lower the pressure of air in said chamber from that discharged by said nozzles.

3. In a furnace, the combination with a front having a central opening through which fuel is fed and a grate for supporting the fuel bed, of a conduit extending transversely across said front adjacent thereto on the inner side thereof and below the top of said grate, said conduit forming a hearth plate and a cooling means for said front, means for supplying cool air to said conduit at a predetermined pressure above atmosphere, and means for discharging the air after passing through said conduit and being heated thereby into the combustion chamber above the grate.

ROYCE L. BEERS. 

